1. Field of the Invention
The present invention relates to an information supplying method, a medium including an information supplying program stored thereon, and an information supplying apparatus, which are advantageous in particular when being applied to a WWW (World Wide Web) server for supplying, to a client via a net work, a requested HTML (Hyper Text Markup Language) file and a JPEG (Joint Photographic Experts Group) image linked to that HTML file.
2. Description of the Related Art
Net surfing is now very popular. A lot of people are enjoying accessing various WWW servers via the Internet using a WWW (World Wide Web) browser running on a personal computer to read character information and associated image information of Web pages (also referred to as home pages) or listen to audio files such as a music file supplied from WWW servers.
To access a desired Web page, a user operates a personal computer on which a WWW browser is running so as to send a message to a WWW server to request that an index file in the HTML (Hyper Text Markup Language) format and an image file linked to that HTML file be transmitted.
Hereinafter, Web page files including an index file and other files such as an image files linked to the index file are collectively referred to as an HTML file.
In WWW systems, any Web page is specified by an address called a URL (Uniform Resource Locator) which uniquely identifies a file on the Internet. Each URL consists of a scheme name, a domain name (host name), and a file name. For example, in the case of a URL “http://www.test.com/index.html”, its scheme name is “http” (Hyper Text Transfer Protocol), and its domain name and file name are “www.test.com” and “index.html”, respectively. In practice, access to a WWW server is performed in accordance with an IP address which is acquired on the basis of the domain name. More specifically, before accessing the WWW server, the WWW browser acquires the IP address of the WWW server by asking a DNS (Domain Name Server) about the IP address.
If a WWW server receives a request for an HTML file specified by a URL, the WWW server transfers via the Internet a Web page including the requested HTML file and other files such as an image file linked to that HTML file to the personal computer which has issued the request (that is, to the personal computer which is accessing the WWW server).
Upon reception of the Web page including the HTML file and other files such as an image file linked to that HTML file, the personal computer displays character information contained in the HTML file and image information linked to the HTML file on the screen of the WWW browser running on the personal computer.
When a user has his/her own Web page stored in a WWW server managed by an Internet service provider or the like, if the user updates his/her Web page via a network, the Web page including HTML files (index.html, for example) currently stored in the WWW server is generally overwritten, that is replaced, with new data except for the case where a Web page is uploaded for the first time. Also in the case where an Internet service provider updates an existing Web page being open to clients, the existing Web page is generally overwritten with a new Web page.
If HTML files (index.html, for example) of Web pages are kept fresh by performing updating in the above-described manner, users can read a Web page including newest information simply by inputting the same URL (for example, “http://www.test.com/index.html”) or by specifying the same URL using a bookmark capability of a WWW browser.
Although updating of HTML files (index.html, for example) of Web pages stored in a WWW server to newest data at an arbitrary time brings about an advantage that clients can access newest information, a disadvantage is in that when a client requests a Web page which was available in a past period but not available now, the WWW server cannot present such a Web page to the client.
In view of the above, it is an object of the present invention to provide a technique of automatically creating a backup file of a past Web page or a Web page which will be released in the future and saving it in a WWW server thereby making it possible to present it to a client in response to a request issued by the client.